1. Field of the Invention
The present invention relates to a micro-pump and, more particularly, to an electromagnetic micro-pump.
2. Description of the Related Art
Taiwan Patent No. I256374 (with a patent publication number of 200611872) entitled “PDMS VALVELESS MICRO-PUMP STRUCTURE AND PROCESS FOR MAKING THE SAME” discloses a PDMS (polydimethylsiloxane) structure, a diaphragm, and a piezoelectric actuator. The PDMS structure includes an upper face having a cavity. The upper face further includes an input groove and an output groove that are in communication with the cavity. The input and output grooves extend to a lower face of the PDMS structure to form an input opening and an output opening. The diaphragm is mounted on the upper face of the PDMS structure to seal the input groove and output groove and includes a central opening aligned with the cavity. The piezoelectric actuator is sealingly fixed in the central opening of the diaphragm.
In use, the input opening is connected to a fluid source, and the piezoelectric actuator is actuated by electricity. When the piezoelectric actuator deflects in a direction away from the cavity, a pressure difference is created to cause flow of the fluid from the fluid source toward the input groove. When the piezoelectric actuator deflects toward the cavity, the piezoelectric actuator creates pressure on the fluid in the cavity, moving the fluid toward the output groove. By repeatedly vibrating the cavity through operation of the piezoelectric actuator, the fluid flows from the input opening into the input groove and then exits the output groove via the output opening.
However, the vibrational displacement of the piezoelectric actuator is small, such that the micro-pump can only be driven by high frequency vibration and, thus, consumes a larger amount of energy. Furthermore, the piezoelectric actuator is made of expensive piezoelectric material, leading to an increase in the costs of the micro-pump.